Executive Summary

For more than a decade, organizations such as
True Love Waits have encouraged young people to abstain from sexual
activity. As part of these programs, young people are encouraged to
take a verbal or written pledge to abstain from sex until
marriage.

A recent article by professors Peter Bearman
and Hanna Bruckner in the Journal of Adolescent Healthclaimed that, when they reach young
adult years, adolescents who made virginity pledges were as likely
to have sexually transmitted diseases (STD's), as were those who
never made a pledge. Bearman and Bruckner did not measure whether
individuals had ever had an STD or had had an STD during
adolescence. They only measured whether young adults were currently
infected with an STD. Since seven or more years might have elapsed
between the time an adolescent made a virginity pledge and the time
STD's were measured, their analysis poses a very rigorous test for
virginity pledges. It assesses the long-term health consequences of
moral commitments made in adolescence.

Bearman and Bruckner's analysis showed that,
as young adults, virginity pledgers actually had lower STD rates
than non-pledgers, but that the differences were not statistically
significant. They concluded that the STD rate of pledgers "does not
differ from non-pledgers." This assertion garnered very widespread
press attention. Bolstered by this finding, Bearman and Bruckner
called for the critical re-examination of federal funding for
abstinence education.

Examination of the Bearman and Bruckner
article reveals that the methods employed have serious limitations.
For example, the methods used to assess the impact of virginity
pledges on STD's also demonstrate that condom use has no effect in
reducing STD's. This peculiar result underscores the problematic
nature of their analysis.

In the present paper, we re-examine the
linkage between adolescent virginity pledging and STD rates among
young adults using the same data set employed by Bearman and
Bruckner, the National Longitudinal Study of Adolescent Health (Add
Health). The current analysis differs in two key respects from
Bearman and Bruckner's. While Bearman and Bruckner used only one
STD measure (the presence of three STD's in urine samples), the
present paper analyzes five STD measures based on urine samples,
STD diagnoses, and STD symptoms. Second, the Bearman and Bruckner
article was unusual in that it presented only simple descriptive
statistics; the present paper employs a wide range of multivariate
logistic regressions that simultaneously hold constant relevant
background variables such as race, gender and family
background.

Our analysis shows that with four of the five
STD measures examined, virginity pledging predicts lower STD rates
among young adults with statistical significance at the 95 percent
confidence level or better. With the fifth STD measure, virginity
pledging was found to predict lower STD rates at the 90 percent
confidence level. (This fifth STD measure was the one employed by
Bearman and Bruckner: evidence of any of three STD's in urine
samples.)

We also analyze the relationship between
condom use and STD rates. Three measures of condom use were
examined: condom use at last intercourse; condom use at first
intercourse and frequency of condom use in the last year. Across
the full range of analysis, using all five dependent STD variables,
virginity pledging was found to be a better predictor of reduced
STD rates when compared to any of the condom use variables.
Critically, none of the condom use variables successfully predicts
lower STD rates with the STD measure chosen by Bearman and Bruckner
(three STD's in urine samples); a fact the emphasizes the
problematic nature of that STD variable as a measure of program
success.

Bearman and Bruckner's conclusion that
virginity pledgers have the same STD rates as non-pledgers is
clearly the result of serious limitations in their analytic
methods. Our current paper shows that taking a virginity pledge in
adolescence is associated with a substantial decline in STD rates
in young adult years. Across a broad array of analysis, virginity
pledging was found to be a better predictor of STD reduction than
was condom use. Individuals who took a virginity pledge in
adolescence are some 25 percent less likely to have an STD as young
adults, when compared with non-pledgers who are identical in race,
gender, and family background. The reduction in STD's for virginity
pledgers occurs despite the fact that many years may have elapsed
between the time the individual took a virginity pledge and the
time that the STD rate was measured. Moreover, after
initially taking a pledge, relatively few virginity pledgers will
have received continuing social support for their commitment to
abstinence.

Lower STD rates is just one among a broad
array of positive outcomes associated with virginity pledging.
Previous research has shown that, when compared to non-pledgers of
similar backgrounds, individuals who have taken a virginity pledge
are:

Less likely to have children
out-of-wedlock;

Less likely to experience teen
pregnancy;

Less likely to give birth as teens or young
adults;

Less likely to have sex before age 18;
and,

Less likely to engage in non-marital sex as
young adults.

In addition, pledgers have far fewer life-time
sexual partners than non-pledgers. There are no apparent negatives
associated with virginity pledging: while pledgers are less likely
to use contraception at initial intercourse, differences in
contraceptive use quickly disappear. By young adult years, sexually
active pledgers are as likely to use contraception as
non-pledgers.

Introduction

For more than a decade, organizations such as
True Love Waits have encouraged young people to abstain from sexual
activity. As part of these programs, young people are encouraged to
take a verbal or written pledge to abstain from sex until marriage.
In recent years, increased public policy attention has been focused
on adolescents who take these "virginity pledges," as policy-makers
seek to assess the social and behavioral outcomes of such
abstinence programs.

In the April 2005 issue of the Journal of
Adolescent Health,professors
Peter Bearman and Hannah Bruckner claimed that adolescents who have
taken a virginity pledge have the same rate of STD infections as
those who have never taken a pledge.[1] This finding was
surprising since previous research had shown that taking a
virginity pledge was clearly associated with reductions in sexual
risk behavior, specifically a delay in initiation of sexual
intercourse and decrease in the number of lifetime sexual partners.
Bearman and Bruckner suggested that while virginity pledging may be
related to a reduction in STD's in early adolescence, by young
adulthood any positive health effects had disappeared. They stated,
"As a social policy, pledging does not appear effective in stemming
STD acquisition among young adults."[2] The authors called for
a re-examination of federal funding for abstinence
education.

Bearman and Bruckner's claim was immediately
seized on by the press and repeated in hundreds of publications
nationwide. For example,

The Associated Press wire service reported,
"teens who pledged abstinence are just as likely to have STDs as
their peers."[3]

The San Francisco Chroniclestated "Virginity pledgers are just as
likely to contract sexually-transmitted diseases as other teens."
[4]

The CBS news show Sixty Minutesreported, "kids who take virginity
pledges [are] just as likely to have sexually transmitted diseases
as kids who don't."

Bearman and Bruckner's finding has quickly
become a key element in the advocacy of groups hostile to
abstinence education. For example, the nation's leading
anti-abstinence organization, the Sexuality Information and
Education Council of the U.S. (SIECUS) triumphantly proclaims
"pledgers have the same rate of sexually transmitted diseases
(STDs) as their peers who had not pledged."[5]

Clearly, virginity pledge programs and
abstinence education are of considerable public and political
interest. Previous research by the authors of the present paper has
shown that adolescents who take virginity pledgers have
substantially improved life outcomes; specifically, they are: less
likely to engage in sexual activity while in high school; have
fewer sexual partners; are less likely to experience teen
pregnancy; and are less likely to bear children out-of-wedlock.[6] The current paper will
examine the link between virginity pledging and sexually
transmitted disease with specific reference to the Bearman and
Bruckner article.

Background

Our analysis will utilize the same database
employed by Bearman and Bruckner, the National Longitudinal Study
of Adolescent Health (hereafter simply "Add Health"), funded by the
Department of Health and Human Services and other federal
agencies.[7]
The Add Health survey is longitudinal which means that it surveys
the same group of youth repeatedly over time. Interviews were
conducted in three succeeding periods: wave I in 1994, wave II in
1995, and wave III in 2001. When the Add Health survey started with
wave interviews in 1994, most of the respondents were junior-high
and high-school students nearly all aged 12 to 18. The students
were tracked through high school and into early adulthood. By the
time of the wave III interviews, the youth in the survey were
nearly all young adults between the ages of 19 and 25.

Virginity Pledgers and Non-pledgers

In each of the three waves of the Add Health
survey, youth were asked the question: "Have you ever taken a
public or written pledge to remain a virgin until marriage?" In the
following analysis, youth who reported, in any of the three waves
of the survey, that they have taken a pledge are counted as
"pledgers". Youth who did not report taking a virginity pledge in
any of the Add Health interview waves are counted as
"non-pledgers." Roughly one fifth of the youth in the Add Health
survey report having taken a pledge in at least one interview of
the survey. The remaining four fifths have never reported taking a
pledge.

As Table 1 shows, pledgers are similar to
non-pledgers in race, family structure, and family income.
Pledgers, in the sample, are slightly younger than
non-pledgers. Pledgers are more likely to be female: 61.8 percent
of pledgers are girls compared to 46.6 percent of non-pledgers.
Pledgers are also somewhat more likely to be religious; on a scale
of one to four based on frequency of church attendance, frequency
of prayer, and importance of religion to the individual, pledgers
have a mean score of 3.4 compared to 2.7 for non-pledgers.

Virginity Pledging and Sexual Activity

Pledging is linked to large reductions in
sexual activity during adolescence. For example, 63 percent of
non-pledgers had sexual intercourse before age 18 compared to 39
percent of pledgers.[8]
As noted, by the third wave of the Add Health survey in 2001, the
adolescents in the survey had become young adults, with ages
ranging between 19 and 25. At this point many years may have
elapsed since the youth's promise to remain a virgin until
marriage. In the intervening years, relatively few pledging youth
will have benefited from social support systems aimed at bolstering
their commitment to abstinence. As a consequence, it is not
surprising that differences in sexual behavior between pledgers and
non-pledgers diminish somewhat over time. Nonetheless, by the third
wave of the survey, real differences in sexual behavior remain;
roughly a fifth of all pledgers have never engaged in any type of
sexual activity (vaginal, oral, or anal) compared to 8 percent
among non-pledgers.

STDs and the Add Health
Survey

Virginity pledge and abstinence education
programs have a variety of goals. Such programs seek to: improve
the mental health of youth; help youth develop true respect for
others; prepare young people for healthy marriages as adults;
reduce the risk of teen pregnancy and out-of-wedlock childbearing;
and reduce the threat of sexually transmitted diseases. As noted,
virginity pledging has been shown to be linked to a wide range of
positive outcomes for youth; however, recently, most attention has
focused on the association between virginity pledges and
STDs.

While the Add Health survey has an abundance
of data on STD's, most are imperfect as means of assessing the
impact of virginity pledging in reducing STDs. One would expect a
virginity pledge program to have its maximum impact in reducing
exposure to STDs in the years immediately after the pledge was
taken. The peak effectiveness of pledge programs in decreasing STDs
probably occurs in late adolescence, the time when the behavioral
differences between pledgers and non-pledgers are greatest and the
risk of acquiring STDs is highest.

To measure the impact of virginity pledges on
contraction of STDs, analysts would ideally want to know: whether a
youth has ever been infected by a STD; the number of infections and
the timing of each; and the date the virginity pledge was taken.
Unfortunately, the Add Health survey does not contain this
information. Critically, the Add Health survey does not ask
respondents whether they have ever had an STD. Instead, most of the
STD data in the Add Health survey relate to current or recent STD
infections occurring at the third interview wave of the survey. By
the third wave interview, as noted, the respondents are no longer
adolescents, but are young adults aged 19 to 25. Many years may
have passed since an individual made his or her virginity pledge.
Thus, the Add Health data provide an imperfect basis for measuring
the link between pledging and STDs.

While the question of whether virginity
pledges, taken mainly in adolescence, are linked to lower STD rates
among young adults is a valid research topic, this approach is very
likely to underestimate the effectiveness of pledging in reducing
STD infections. Bearman and Bruckner partially acknowledge this
point, stating that STD data on young adults "cannot tell us
whether pledgers had a lower risk of STD infection as young
adolescents."[9]
With this caveat in mind, the present paper will follow the
approach taken by Bearman and Bruckner, measuring the relationship
between adolescent virginity pledging and subsequent STD rates
among young adults. Again, readers should recognize that this
methodology, while informative, is very likely to underestimate the
health benefits of pledging.

Bearman and Bruckner's STD Analysis

To analyze the links between virginity
pledging and STD's, Bearman and Bruckner used STD data from the
third interview wave of the Add Health survey. As part of the third
wave interviews, urine samples were taken from some 90 percent of
Add Health respondents, a total of around 14,000 individuals. The
urine samples were examined for evidence of current bacterial
infection by three sexually transmitted diseases: Chlamydia,
Gonorrhea, and Trichomoniasis. According to the urine sample data,
some 6.8 percent of the sample was found to be currently infected
with one or more of these diseases.

Bearman and Bruckner then determined the
pledge status of each interviewee based on data from all three
waves of the Add Health survey. On the basis of this analysis, they
concluded that "the STD infection rate [of virginity pledgers] does
not differ from nonpledgers"[10] This claim has been
repeated on television and in hundreds of news stories and has been
amplified by other groups.

We shall begin our examination of these claims
by reporting the actual STD infection rates in the Add Health
sample. Chart 1 shows the STD rates for pledgers and non-pledgers;
the measure of STD infection is the same one employed by Bearman
and Bruckner: evidence of Chlamydia, Gonorrhea or Trichomoniasis in
urine samples. (We shall henceforth refer to this variable as the
"three STD's in urine sample" measure.)

Given the aggressive claims of the press and
anti-abstinence groups, many will be surprised to find that the Add
Health survey data used by Bearman and Bruckner actually show that
pledgers have noticeably lower STD infection rates than do
non-pledgers. Male pledgers have an infection rate 30 percent lower
than non-pledgers (4.2 pecent to 6.1 percent.) Female pledgers have
an infection rate some 15 percent lower than non-pledgers (6.7
percent to 7.8 percent.) These differences are roughly in line with
what might be expected given that the behavioral differences
between the two groups have attenuated by young adulthood.

If the Add Health data show pledgers have
lower rates of infection, how can Bearman and Bruckner assert that
the STD rate of pledgers "does not differ" from non-pledgers? At
the foundation of their argument is the legitimate issue of
"statistical significance". Obviously, the Add Health survey does
not contain all American youth; it is a representative sample of
some 15,000 individuals. In analyzing data from the sample, it is
important to estimate whether conditions in the sample: a) reflect
real conditions in the U.S. population as a whole; or, b) may be
the result of random distortion in the sample itself. (If, for
example, we took a sample of 10 persons and found that seven were
men, it would not be appropriate to conclude that 70 percent of all
persons were male.) Statistical significance measures the degree of
confidence that analysts can have that conditions found in the
sample mirror conditions in the real world.

Bearman and Bruckner found that the
differences in STD rates between pledgers and non-pledgers were not
statistically significant at the 95 percent confidence level, a
conventional test of significance used in social science. In other
words, while the Add Health survey shows differences in STD rates,
we cannot be 95 percent certain that these differences exist in the
general youth population rather than just within the confines of
the Add Health sample.

It is true that, using the urine sample
measure of three STDs, the differences in STD rates between
pledgers and non-pledgers are not statistically significant at the
95 percent confidence level. But the differences in STD rates do
fall within a hairbreadth of the 95 percent significance threshold.
Multivariate regressions (presented later), using the three STD's
in urine sample measure as the dependent (predicted) variable
reaffirm that pledgers have lower rates of STDs; this finding is
significant at the 91 to 94 percent confidence levels.[11]

While technically accurate, Bearman and
Bruckner's claim that "the STD infection rate [of virginity
pledgers] does not differ from nonpledgers" represents rather
severe example of the "null hypothesis fallacy." In effect, they
argue: differences in STD rates between pledgers and non-pledgers
appear in the Add Health sample, but these differences are
significant at the 90 percent rather than the 95 percent confidence
level, therefore we assert categorically that no STD differences
exist between the two groups. The fallacy of this logic is obvious.
A passionate embrace of the null hypothesis (no differences in
outcomes exist between the groups) is likely to be misplaced when
the STD differences found in the sample are near the 95 percent
confidence level and where other evidence exists indicating that
these STD differences are real. As we shall see this is the
situation with respect to virginity pledges and STDs.

Part of the difficulty of demonstrating
statistical significance may lie in the particular STD measure used
by Bearman and Bruckner. The three STD in urine sample measure
shows a very low rate of current STD infection; only 6.8 percent of
young adults have an STD by this measure. In addition, virginity
pledgers are a relatively small group, comprising roughly 20
percent of the Add Health sample. Overall, pledgers testing
positive for the three STDs in the urine sample were about one
percent of the Add Health sample. These factors make it difficult
to demonstrate statistically significant effects. Other measures of
STD infection in the Add Health data base may more readily yield
statistically significant results.

Other Measures of STD Infections

In addition, to the urine sample test, the
third wave of the Add Health survey contains other STD data:
respondents are asked if they have been diagnosed as having one of
fourteen different STDs in the last twelve months; they are also
asked if they have had specific physical symptoms of STD infection
in the last year. We have utilized these additional data to
construct five different measures of STD infection.

A. Three STDs in urine sample. We code respondents as having an
STD if their urine sample shows the presence of Gonorrhea,
Chlamydia, or Trichomoniasis. This is the same measure used by
Bearman and Bruckner.

B. Three STDs in urine sample or three STD
diagnosis. In addition
to testing urine for Chlamydia, Gonorrhea, and Trichomoniasis, Add
Health also asks the individual if they have been diagnosed as have
any of these three diseases in the last 12 months. For this
measure, we code individuals as having an STD if they have a
positive urine test or have been diagnosed as having one or more of
the three diseases in the last year. Gonorrhea, Chlamydia, and
Trichomoniasis are bacterial infections. An individual who is
diagnosed with one of these diseases will immediately be given
antibiotics. In nearly all cases, the antibiotic will quickly
eliminate the disease and remove evidence of the disease from the
urine. A urine sample alone will understate the prevalence of these
three diseases since many individuals will already have been
diagnosed and treated for them. Combining the urine sample data
with information on diagnoses during the prior 12 months provides a
more robust and useful measure of STD incidence.

C. Three STDs in urine sample or physical
symptoms. There are many
STDs in addition to the three assayed in the urine samples. This
measure combines the urine sample data with reported physical
symptoms. Under this measure, individuals are coded as having an
STD if they have a positive urine test or if they report having
experienced any of the following physical symptoms in the last
year: "warts on your genitals", "painful sores or blisters on your
genitals" or "oozing or dripping from your penis or vagina".[12]

D. Diagnosis of having any of fourteen
STDs. The Add Health
survey also asks respondents if, in the last 12 months, they have
been told by a doctor or health worker that they have any of the
following sexually transmitted diseases: chlamydia, gonorrhea,
trichomoniasis, syphilis, genital herpes, genital warts, human
papilloma virus (HPV), bacterial vaginosis, pelvic inflammatory
disease (PID), crevicitis or mu copurulent cervicitis (MPC),
urethritis (NGU), vaginitis, HIV or AIDS, or other STD. Under this
measure, individuals are coded as having an STD if they report
being diagnosed with any of the diseases on the preceding
list.

E. Fourteen Disease Diagnosis, positive
urine sample, or physical symptoms. This measure combines the previous four
measures. Individuals are coded as having an STD if they: have a
positive urine test; have any of the three physical symptoms; or
have been diagnosed with any of the fourteen STDs in the last
year.[13]

Chart 2 shows the incidence and 95 percent
confidence intervals for each of the five STD measures. (The
confidence intervals indicate that we can have 95 percent certainty
that the infection rate in the real world falls within the interval
range.) The three STD urine sample measured used by Bearman and
Bruckner has the lowest point estimate of incidence (at 6.7
percent) and the largest confidence interval relative to the point
estimate. This indicates that it will be comparatively more
difficult to make statistically significant predictions with this
STD measure compared to the others.

We hypothesize that virginity pledge status is
more likely to be a statistically significant predictor of reduced
STD infection for the STD measures with higher incidence. We
hypothesize further that the same pattern will hold between condom
use variables and STD measures. Confirmation of these hypotheses
will provide compelling evidence that Bearman and Bruckner's
failure to find significant differences in the STD rates of
pledgers and non-pledgers was a result of the operational measure
of STD's they employed.

The Role of Social Background
Variables

Teens who make
virginity pledges may differ substantially from those who do not in
a wide range of important social background factors. If pledgers
have better STD outcomes than do non-pledgers, it is possible that
the outcome differences are the result of social background factors
rather than pledge activity per se. To compensate for this
possibility, we analyzed the role of virginity pledges on STD
outcomes through a set of multivariate logistic regression analyses
which hold relevant social background factors constant. In this
statistical procedure, teens who made virginity pledges were
compared to non-pledging teens who were otherwise identical in
social background characteristics.

A number of independent or predictor variables
were used in the regression analyses. These were:

Pledge status
­­­­-Individuals were identified as
"pledgers" if they responded that they had made a virginity pledge
in at least one wave of the survey. Individuals were identified as
"non-pledgers" if they answered that they had not taken a virginity
pledge in each of the three waves of the survey.[14]

Gender - whether
the individual was male or female

Age - whether the
individual was white, black, Asian or Hispanic

Family background -
whether the individual came from an intact married family
containing both biological parents, a single parent family, a step
parent or cohabiting family or other family.

Religiosity - a
continuous variable on a scale of 1 to 4 based on the average
scores of responses to the questions: how often do you attend
religious services, how often do you pray, and how important is
religion to you.

All Add Health youths for which STD data were
available were included in the regressions. The independent or
predictor variables were deployed in four models. These were:

Model One - pledge
status was used as a single predictor variable without
controls.

Model Three - The
independent variables were the same as Model Two but family
structure variables were added.

Model Four - The
independent variables were the same as Model Three but religiosity
was added.

Virginity Pledging as a Predictor of Lower Rates of STD
Infection

To fully examine the relationship between
virginity pledging and the STD rates of young adults, the five
dependent STD measures were each analyzed in all four regression
models described above, yielding a total of 20 separate
regressions. Data on the individual logistic regressions is
provided in the appendix.

Table 2 summarizes the results of the 20
regressions. Using all five dependent STD variables, virginity
pledgers were found to have lower STD rates across all 20
regressions; in each case the odd ratios for pledging were below
1.00 indicating that pledging was linked to lower STD rates.
Virginity pledging was found to be a statistically significant
predictor of lower STD rates at, at least, the 95 percent
confidence level, for four of the STD measures: (B) three STDs in
urine or three STD diagnosis; (C) three STD's in urine or physical
symptoms; (D) diagnosis of any of 14 STDs; and, (E) diagnosis of 14
STD's positive urine sample or physical symptoms. In many cases,
statistical significance reached the 99 percent confidence level.
(The sole exception to these results was STD measure (C) in model
one, a regression without controls; the results here were not
significant.)

The regression models using STD measure (A) or
three STDs in urine sample, as the dependent variable, differ
somewhat from the other regressions. This is the STD measure
employed by Bearman and Bruckner. All four models using STD measure
(A) show that virginity pledgers have lower STD rates than
non-pledgers. The magnitude of STD reduction (odds ratio) is
virtually identical to the other sixteen regressions using STD
measures (B), (C), (D), and (E) as dependent variables. However,
the models using STD measure (A) as a dependent variable fall just
short of the 95 percent statistical significance level. With this
STD measure, in models 2, 3, and 4, virginity pledge status is
shown to be statistically significant as a predictor of reduced
STDs at the 92 to 94 confidence level. Unfortunately, STD measure
(A) is the only one employed in Bearman and Bruckner's
analysis.

In summary, in all cases the Add Health data
show that virginity pledgers have lower STD rates when compared to
non-pledgers. In four of the five STD measures presented, virginity
pledging predicts lower STD rates with a statistical significance
of 95 percent or greater. With the fifth STD measure, virginity
pledging is shown to predict lower STD rates with a 90 percent
confidence. No STD measures in the Add Health survey show virginity
pledgers to have same or higher STD rates as non-pledgers. In view
of this aggregate data, it is implausible to conclude that pledgers
and non-pledgers in reality have the same STD rates. Bearman and
Bruckner's conclusion that there were no meaningful differences in
STD rates between pledgers and non-pledgers is contingent on the
single STD measure they employ. Moreover, even with this measure,
virginity pledging falls short of statistical significance by a
razor thin margin.

Condom Use and STD's

The next step in our analysis was to examine
the relationship between STD's and an array of measures of condom
use. This enables us to compare the efficacy of virginity pledges
and condom use as predictors of STD's. It also provides an
independent method of assessing the utility of various measures of
STD infection. We hypothesized that those STD measures that lacked
a statistical significant association with the virginity pledge as
a predictor would also lack a statistically significant link to
condom use as a predictor. If true, this could underscore the
problematic nature of those dependent STD variables.

Using Add Health interview data, we
constructed three independent (predictor) variables for condom use.
They were:

Condom Use at
First Vaginal Intercourse.
This measures whether an individual used a condom during the first
instance of intercourse in his or her life. The variable is a three
part dummy variable: never had vaginal intercourse; had vaginal
intercourse and used condom in first intercourse; and had vaginal
intercourse and did not use condom in first intercourse. (The last
category was the default.)

Condom Use in
Last Vaginal Intercourse. This
variable measures whether a condom was used during last
intercourse. It is a three part dummy variable: never had vaginal
intercourse; had vaginal intercourse and used a condom during last
intercourse; and, had intercourse and did not use a condom during
last intercourse. (The last category was treated as the
default.)

Frequency of
Condom Use. For individuals
who report they had vaginal intercourse during the last year, the
Add Health survey asked how frequently condoms were used during
intercourse: never; some of the time; half of the time; most of the
time; or, all of the time. A five point continuous independent
variable was created with these responses. Regressions using this
variable were necessarily limited to those who reported having
vaginal intercourse during the last year.

We tested each of these condom use variables
as predictors of the five dependent STD measures. Socio-economic
control variables were used according to the four models specified
earlier in the paper. A total of twenty logistic regressions were
performed using each of the three independent variables of condom
use, for a total of 60 regressions in all. (Information on the
individual regressions is presented in the appendix.)

The results are summarized in table 3. Each of
the condom use independent variables either fails to predict or
predicts inadequately with respect to the three STD measures at the
top of the table: three STDs in urine sample; three STDs in urine
sample or three STD diagnoses; and three STDs in urine sample or
physical symptoms. Using these three STD measures as dependent
variables, statistical significance is not achieved in 27 of 36
regressions; in 9 regressions, significance reaches the 90 percent
confidence level.

The two STD measures at the bottom of the
table (diagnosis of fourteen STD's, and diagnosis of fourteen STD's
combined with positive urine sample or physical symptoms) present a
different story. With these STD measures, the three condom use
variables are able to predict, in almost all models, a reduction of
STD's at 95 or 99 percent confidence levels. These patterns of
significance loosely match those found with virginity pledge
variable. The data in table 3 underscore the fact that statistical
significance of predictor variables is highly contingent on the
particular STD measure used. The data suggest that it would be
unwise to base conclusions on one measure only.

The failure of all three condom use variables
to successfully predict reductions in Bearman and Bruckner's chosen
STD measure (a positive test for 3 STD's in the urine sample) is
important. The condom use variables not only failed to predict a
reduction in STD's according to this measure, they failed very
badly. (Specific information is provided in regression tables 6,
11, and 16 in the appendix.) While the virginity pledge variable
predicted STD reduction at the 90 percent confidence level
according to this STD measure, the condom use independent variables
achieved, at best, a 35 percent confidence in predicting reductions
in this STD variable. One variable actually achieves a
statistically significant prediction of increased STD's using this
STD measure under model I. This is undoubtedly a fluke, but it
calls attention to the problematic nature of the three STDs in
urine sample measure as a dependent variable.

Comparison of Virginity Pledge and
Condom Use as Predictors of STD Reduction

Table 4 compares the predictive power of the
virginity pledge variable to the predictive power of the condom use
variables (condom use at first intercourse, condom use at last
intercourse and frequency of condom use in last year). The
virginity pledge variable predicts a reduction in STD's with at
least a 95 percent confidence with four of the five dependent STD
variables. It predicts reduction in the fifth STD variable with 90
percent confidence. By contrast the three condom use variables
predict reductions at 95 percent confidence with only two of the
five STD measures.

The virginity pledge variable predicts reduced
STD's at the 99 percent confidence with three STD variables. It
predicts at 95 percent confidence with the fourth STD variable and
90 percent with the fifth STD measure (A). By contrast, the most
effective condom use variable (condom use at first intercourse)
predicts STD reduction at the 99 percent confidence level with one
measure and at the 95 percent confidence with another. It achieved
90 percent confidence with two other STD measures and failed to
predict with the final dependent measure (A): three STD's in urine
sample.

Overall, in the analysis 80 regressions were
performed: 20 with the virginity pledge variable and 60 with the
three condom use variables. In every instance, across all 80
regressions, the virginity pledge variable always achieved higher
levels of confidence as a predictor of STD reduction when compared
to any of the corresponding condom use variables. In other words,
in predicting reduction of each dependent STD variable in each of
the four regression models, the virginity pledge variable always
outperformed all the condom variables. While it is possible that
future research may improve the predictive power of both the pledge
variable and the condom use variables, it is very difficult in
light of the evidence in table 4 to conclude, as Bearman and
Bruckner did, that "the STD infection rate [of pledgers] does not
differ from non-pledgers".[15]

Finally, note that the comparison of virginity
pledging against condom use is unfair to virginity pledge programs
because it compares pledging, which is merely a promise to behave a
certain way in the future, against actual behavior: the use of
condoms. A fair comparison would be to contrast the outcomes of
virginity pledges against adolescent promises to use condoms in the
future. Of course, no "condom promise" programs exist; if they did
they would be unlikely to compare well against virginity pledge
programs.

Methodological Differences with Bearman and Bruckner
Analysis

While the present analysis and the
Bearman-Bruckner article both used the same Add Health database,
they reached very different conclusions concerning the relationship
between the virginity pledges and STD's. These differences stem
from three factors.

First, and most obvious, Bearman and Bruckner
examined only one measure of STD occurrence whereas the present
paper examines five. Second, the Bearman and Bruckner article
presented only simple descriptive statistics and confidence
intervals. The present paper relies primarily on multivariate
logistic regressions. The use of simple descriptive data can cause
difficulties when groups compared differ in background
characteristics. In this case, the fact that pledgers are more
likely to be women and that women are more likely to have STD's is
particularly relevant.

Third, the Bearman and Bruckner article
divided Add Health respondents into three categories: non-pledgers,
inconsistent pledgers, and consistent pledgers.[16] Structuring the pledge
data in this way, Bearman and Bruckner actually found, as expected,
that non-pledgers had the highest STD rates, followed by
inconsistent pledgers in the middle, while consistent pledgers had
the lowest rates; however, the differences were not statistically
significant. This three-part division of pledge status is
heuristically useful, and the present authors have successfully
used it in previous research; however, it does have drawbacks.
Dividing the already small population of pledgers into two smaller
sub-groups reduces the probability of achieving statistically
significant predictions. Consequently, in the present paper, we
have followed the Bearman and Bruckner's approach to pledge status
closely, but the two categories of inconsistent and consistent
pledgers have been combined into the single group called
"pledgers."

Considerations on Differences in STD Measures

If pledgers and non-pledgers truly had
identical rates of STD infection, one would expect to see a wider
variation in outcomes across various STD measures; some STD
measures would probably show the pledgers had higher disease rates;
others would show the STD rates of pledgers and non-pledgers to be
nearly identical, and other measures would show pledgers to have
lower rates. The Add Health data clearly do not show this pattern;
all five STD measures show that pledgers have lower STD rates. The
only real difference between the five STD measures is that four
show the relationship between pledging and reduced STD's is
significant at the 95 to 99 percent confidence levels while the
fifth measure shows significance at a 90 percent confidence. This
seems to build a prima facie case that virginity pledgers do have
lower STD rates in their young adult years despite the fact that
many years may have elapsed since they took their pledges.

Despite the array of different STD data
available from the Add Health survey, Bearman and Bruckner analyzed
only the urine sample data. They apparently regard the Add Health
STD diagnoses data to be biased against non-pledgers, arguing that
non-pledgers are more likely to perceive themselves at risk of
STD's and more likely to go to a doctor and be diagnosed and
treated. Assuming that this idea has some validity, it has
interesting implications. Diagnosis and treatment will remove
evidence of gonorrhea, Chlamydia and Trichomoniasis from the urine.
If it is true that medical diagnoses rates of STD's are biased
against non-pledgers because they are differentially more likely to
be diagnosed and treated for each STD occurrence, it follows that
post-treatment physical evidence (such as the urine sample) would
be biased, conversely, against pledgers.

For example, if it were true, that, 1)
pledgers and non-pledgers have identical rates of pre-treatment STD
infections; and, 2) non-pledgers are more likely to go to a doctor
and be diagnosed and treated, then it would follow that the
post-treatment urine samples should show non-pledgers with lower
rates of current infection. Obviously, this is not the case. This
provides yet another piece of evidence indicating that pledgers do
in fact have lower STD rates than non-pledgers.

Table 5 shows the STD rate ratios for the five
STD measures. The ratios represent the STD rate of pledgers divided
by the STD rate of non-pledgers; they report raw or
non-standardized data. The ratios have inconsistencies but they
provide some evidence suggesting that non-pledgers may, indeed, be
differentially more likely to go to a doctor and be diagnosed per
STD occurrence. The ratio for the 14 STD diagnosis measure (which
is based on diagnosis only) is lower than the other measures based
on physical evidence or physical evidence and diagnosis
combined.

If it is true that non-pledgers are more
likely to seek treatment per STD occurrence, then STD measures
using diagnosis would be somewhat biased in favor of pledgers and
STD measures based on post-treatment physical evidence (such as
urine samples) would be biased against pledgers. The real
inter-group difference would lie somewhere between the urine sample
STD measure and the STD diagnosis measure.

The question of biases in the STD measures
would be critical if the different STD measures presented opposite
findings: if one measure showed pledgers had better outcomes while
another showed non-pledgers had better outcomes. But, of
course, all the STD measures show pledgers have better
outcomes.

Again, if the real pre-treatment STD rates for
pledgers and non-pledgers were identical we would expect that the
urine measure would show non-pledgers with lower STD rates while
the diagnosis measure would show non-pledgers with higher rates. Of
course, this is not the case. All the measures show that pledgers
have lower STD rates; the only difference is between those that
show significance at the 95 or 99 percent confidence level and the
one measure with 90 percent confidence. Thus, the potential bias of
the individual STD measures for or against pledgers does not
disturb the large body of evidence indicating pledgers have lower
STD rates.

Magnitude of Predicted STD Reduction

The power or magnitude of STD reduction
predicted by the virginity pledge variable is fairly constant
across all the regression models. In general, virginity pledgers
were found to have STD rates about 25 percent lower than the STD
rates of non-pledgers of the same gender, race and family
background. This is illustrated in Chart 3. The chart uses the
broadest STD measure: the combined measure of diagnosis of fourteen
STD's, three STD's in the urine or physical symptoms. Chart 3 shows
the predicted STD rates for an Hispanic male age 22 raised in a
step-family. If this individual had never taken a virginity pledge,
the predicted probability of STD's would be 19.9 percent. If he had
taken a virginity pledge, the predicted probability would be around
one fourth lower at 14.6 percent. The chart also shows the
predicted STD rates for a white male, also aged 22 and raised in a
step family. If this individual had never taken a virginity pledge,
the predicted probability of STD's would be 12.5 percent. If he had
taken a pledge, the probability of STD's would be around one fourth
lower or 9.0 percent. Similar STD reductions would occur for
individuals different gender, race or family background.

Other Behavioral
Outcomes

The fact that virginity pledgers are less
likely to have STD's is just one among a broad array of positive
outcomes associated with virginity pledging.[17] Previous research has
shown that, when compared to non-pledgers of similar backgrounds,
individuals who have taken a virginity pledge are:

Less likely to have children
out-of-wedlock;

Less likely to experience teen
pregnancy;

Less likely to give birth as teens or young
adults;

Less likely to have sex before age 18;
and,

Less likely to engage in non-marital sex as
young adults.

Pledgers will have fewer life-time sexual
partners than non-pledgers. Pledgers engaging in sexual activity in
young adult years are as likely to use contraceptives as are
non-pledgers. Pledgers are also less likely to have abortions
although the reported incidence low enough that the difference is
not statistically significant.

Success or
Failure?

Virginity pledge programs provide a strong
positive social message emphasizing: self-control; future
orientation and respect for self and others. Adolescents who make
virginity pledges promise to abstain until marriage. Virginity
programs are often criticized because a majority of those making
pledges fail to meet their goal and do have sex before marriage.
However, this criticism seems misplaced. Even if pledgers fail to
abstain till marriage, pledging is still associated with positive
life decisions. As noted, when compared to non-pledgers, pledgers
are more likely to delay substantially the onset of sexual activity
and to have fewer sex partners. Pledging is linked to strong
positive outcomes for the individual and society.

Given such outcomes, it is difficult to
imagine how virginity pledge programs could be judged failures.
Consider, for example, a hypothetical program in which a group of
adolescents all promised to attend Harvard. Two years later, few
were attending Harvard, but the overall college attendance rate was
up 30 percent compared to adolescents who never made such a
promise. Would such a program possibly be deemed a failure?

Questions of
Causation

This paper has presented a strong finding
showing that adolescent virginity pledging is associated with lower
STD rates. This should not be surprising, because in young adult
years virginity pledgers have lower levels of sexual activity and
fewer sexual partners when compared to non-pledgers. Overall, the
evidence concerning the positive effects of virginity pledges is
extremely strong. Still, skeptics might argue that the simple fact
that teens who make virginity pledges have substantially improved
behaviors does not prove that virginity pledge programs themselves
have a positive impact on behavior. It is conceivable that
participating in a virginity pledge program and taking a pledge
merely ratifies pro-abstinence decisions that the teen would have
made without the program or pledge. From this perspective virginity
pledge programs may be a redundant fifth wheel with no effect,
rather than an operative factor leading to less risk behavior.

The fact that research on the outcomes of
associated with virginity pledging controls for a wide range of
social background variables makes this less likely. Still, given
the limitations of the Add Health data, it is impossible to fully
disprove this type of skepticism. Nonetheless, such an argument
violates common sense. Teens do not make decisions about sexual
values in a vacuum. A decision to abstain and delay sex activity
does not emerge in a teen's mind, ex nihilo,but will reflect the sexual values and
messages that society communicates to the adolescent.
Unfortunately, teens today live in a sex saturated popular culture
that celebrates casual sex at an early age. To practice abstinence,
teens must resist peer and media pressure, as well as control
physical desire. It seems implausible to expect teens to abstain in
the absence of social institutions (such a virginity pledge
programs) that teach strong abstinence values. Similarly, it seems
implausible that programs that teach clear abstinence values will
have no influence on behavior, even among teens who embrace those
values.

Since decisions to practice abstinence do not
emerge in a vacuum, it seems very likely that the messages in
virginity pledge programs contribute to positive behavior among
youth. Participation in virginity pledge programs encourages youth
to make pro-abstinence choices, and taking a public abstinence
pledge reinforces the teen's commitment, helping him to stick with
the abstinence life style.

Public Policy
Issues

Today's teens live in a sex-drenched media
culture that promotes vulgarity, permissiveness and casual sex.
Most parents are eagerly seeking social forces that can counteract
this tide of permissiveness and communicate an uplifting message of
self restraint to youth. Nearly 90 percent of parents want schools
to teach youth to abstain from sex until they are married or in an
adult relationship that is close to marriage.[18] This is the
predominant message of abstinence education programs.

Unfortunately, these parental values are
rarely taught in the classroom. The focus of government continues
to be on "safe sex," or promoting contraceptive use. Today,
government spends, at least, twelve dollars promoting and
distributing contraception for every one dollar spent encouraging
abstinence.[19]
If the comparison is limited to funding for teens, government still
spends at least four dollars promoting contraceptives for every
dollar spent on abstinence. Moreover these figures dramatically
undercount the efforts to promote contraception since they do not
include most state and local spending of sex education, nearly all
of which continues to have a heavy, if not exclusive, emphasis on
contraception.

Today, nearly all students in the U.S. are
taught about contraception[20]; however, students
rarely receive more than token references to abstinence. Authentic
abstinence programs which strongly encourage youth to abstain from
sexual activity are rare. The abstinence programs that do exist are
limited, generally providing 10 to 15 hours of instruction per
year. It is true that, in the limited time available, abstinence
programs teach abstinence not contraception; however, this does not
mean that youth participating in abstinence programs never receive
information about contraception. In schools where abstinence is
taught, students will generally receive information about
contraception as well, in a separate venue such as a biology or
health class. Polling shows that a majority of parents believe
that, if contraception is to be taught, it should be taught
separately from abstinence.[21]

Bearman charges that youth who participate in
abstinence education are ignorant and afraid of contraception. He
states that virginity pledgers "have been taught that condoms don't
work; they're fearful of them. They don't know how to use
them…They have no experience with them. They don't know how
to get them." While it is true that participants in abstinence
programs are taught about the limitations of contraception, there
is no evidence to substantiate the rest of Bearman's claim. The
wave II interviews of the Add Health survey contains a "knowledge
quiz" that section that tests individuals' knowledge of
contraception and reproduction. The differences between pledgers
and non-pledgers in this knowledge are marginal; moreover, the
degree of contraceptive knowledge does not predict lower STD rates.
As young adults, virginity pledgers are no less likely to use
contraception than non-pledgers.[22]

To recapitulate, the general situation in sex
education and sexuality issues in the U.S. is as follows: The vast
majority of government funding is focused on the distribution and
promotion of contraception. Nearly, all youth receive instruction
in contraception. Even where abstinence is taught, students will
generally still receive information about contraception in a
separate school program. Despite the fact that nearly all parents
want youth taught a very strong abstinence message, the real
teaching of abstinence is still relatively rare. Few students
receive more than token references to abstaining.

Remarkably, despite the overwhelming
popularity of abstinence education among parents, there is
currently a vigorous effort to eliminate abstinence education from
the schools, led by groups such as the Sexuality Information and
Education Council of the United States (SIECUS) and Advocates for
Youth. The focal point of this campaign is an effort to eliminate
federal funding for abstinence education. The attack of Bearman and
Bruckner against virginity pledge programs plays a major role in
the advocacy of these groups.

Those seeking is to eliminate abstinence
education wish to replace it with "comprehensive sex ed" programs,
sometimes also called "abstinence plus."[23] While proponents of
these programs claim they emphasize abstinence, content analyses
reveal such curricula contain virtually no abstinence material, in
fact, many such materials implicitly undermine and denigrate
abstinence.[24]
Comprehensive sex ed curricula all convey the message that it is
okay for teens to have sex as long as they use contraception. Only
seven percent of parents agree with that message. Very few parents
want youth taught materials that condone and accept casual sex at
an early age; unfortunately, that is the message contained in
comprehensive sex ed curricula.[25]

The main issue in sex education today is not,
as Bearman and Bruckner apparently believe, whether society should
"ban discussion of contraception and STD protection from sex
education."[26]
As noted, nearly all youth are currently taught about
contraception. The real question is whether youth will be taught
anything besides contraception. Evidence from the virginity pledge
programs indicates that youth can respond positively to messages of
self-restraint contained in abstinence programs. Other evaluations
show that abstinence education is effective in reducing sexual
activity. [27]
Parents want-- and youth need-- more uplifting messages of
self-control from abstinence education, not less.

Conclusion

The analysis of Bearman and Bruckner
indicating that virginity pledgers have the same STD rates as
non-pledgers has garnered widespread media and political attention.
However, the same methods used by Bearman and Bruckner to analyze
virginity pledges also show that condom use has no effect in
reducing STD's. This clearly illustrates the serious limitations of
Bearman and Bruckner's methodology.

The paper has shown that taking a virginity
pledge in adolescence, in fact, is associated with a substantial
decline in STD rates in young adult years. Across a broad array of
analysis, virginity pledging was found to be a better predictor of
STD reduction than was condom use. Individuals who took a virginity
pledge in adolescence are some 25 percent less likely to have an
STD as young adults, when compared with non-pledgers who are
identical in race, gender, and family background. The reduction in
STD's for virginity pledgers occurs despite the fact that many
years may have elapsed between the time the individual took a
virginity pledge and the time that the STD rate was measured.
Moreover, after initially taking a pledge, relatively few virginity
pledgers will have received continuing social support for their
commitment to abstinence.

Other research has shown that, when compared
to non-pledgers of similar backgrounds, individuals who have taken
a virginity pledge are:

Less likely to have children
out-of-wedlock;

Less likely to experience teen
pregnancy;

Less likely to give birth as teens or young
adults;

Less likely to have sex before age 18;
and,

Less likely to engage in non-marital sex as
young adults.

Pledgers will have fewer lifetime sexual
partners than non-pledgers, and pledgers engaging in sexual
activity in young adult years are as likely to use contraceptives
as are non-pledgers.

Virginity pledge and similar abstinence
education programs are among the few forces in our society pushing
back against a tide of sexual permissiveness. These efforts need to
be strengthened and expanded.

[7]This research uses data from Add
Health, a program project designed by J. Richard Udry, Peter S.
Bearman, and Kathleen Mullan Harris and funded by grant P01-HD31921
from the National Institute of Child Health and Human Development,
with cooperative funding from 17 other agencies. Special
acknowledgment is due Ronald R. Rindfuss and Barbara Entwisle for
assistance in the original design. Persons interested in obtaining
data files from Add Health should contact Add Health, Carolina
Population Center, 123 West Franklin Street, Chapel Hill, NC
27516-2524 (addhealth@unc.edu).

[12] The Add Health survey
also asks three other questions about symptoms: "painful or very
frequent urination, bleeding after intercourse or between your
periods [for females only], and itching in the vagina or the
genital area [females only]". We did not include these symptoms in
the STD measure because of the high probability that they were
caused by non-STD factors.

[13] In each of the five
STD measures, individuals are categorized in a binary fashion:
"yes" for having an STD if they report positively on one or more of
the relevant conditions (urine sample test, symptoms, or diagnosis)
and "no" if they report negatively on all the relevant conditions.
The measures, thus, do not reflect the degree of disease; for
example, an individual diagnosed with three diseases would be coded
the same as an individual diagnosed with one disease.

[14] In some cases
individuals failed to answer the pledge question on one or more
waves of the survey; an individual who responded negatively to this
question on at least one wave and gave no response on the other
waves was categorized as a non-pledger.

[16]Consistent pledgers are
individuals who affirmed in at least one wave of the survey that
they had made a pledge and did not provide contradictory
information in any subsequent wave. Inconsistent pledgers reported
that they had ever taken a pledge in at least one wave of the
survey, but then contradicted themselves by reporting they had
never taken a pledge in a subsequent wave. In our analysis, we were
able to precisely duplicate Bearman and Bruckner's pledge
categorization. As noted, for purposes of the present paper, we
merged the inconsistent and consistent pledgers into the single
category of pledgers.

[20]Eighty percent of
7-12th grade students report that their most recent sex
education course was considered comprehensive. 82 percent of
7-12th grade students report receiving information about
birth control in their sex education course. See The Kaiser Family
Foundation, Sex Education in America: A Series of National
Surveys of Students, Parents, Teachers, and Principals, September 2000, pgs. 17-18.

[22]While it is true, that virginity
pledges are less likely to use contraception during their very
first experience of intercourse, by young adult years differences
in contraceptive use between sexually active pledgers and
non-pledgers have completely disappeared. The main importance of
contraceptive or condom use at first intercourse as a variable is
that it predicts subsequent contraceptive use; lower rates of
contraceptive use at first intercourse may indicate lower
contraceptive use in later years. However, as noted, sexually
active virginity pledgers are not less likely to use contraceptives
by Wave III of the Add Health survey. Thus, the fact that pledgers
are less likely to contracept at first intercourse seems to have
little significance.

[25]A major reason that law
governing the federal funding of abstinence education stipulates
that funded abstinence programs should not teach or promote
contraceptive use is to prevent the piracy of abstinence funds by
pseudo "abstinence plus" programs that pretend to teach abstinence,
but, in reality, denigrate it.

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